This paper introduces the characterization of AZ-P4620 photoresist as a sacrificial layer for Radio Frequency MEMS (Micro-Electro-Mechanical System) switches. The surface micromachining process is opted for the fabrication of RF MEMS switches, which includes a suspended structure. Initially, a thick photoresist is coated and patterned, to be utilized as a sacrificial layer and then the structural layer is deposited on it. For proper connectivity of the structural layer, edge coverage is required. This photoresist is optimized at different post-baking temperatures. We investigated that slope angles decrease with an increase in post bake temperature. Using the optimized recipe, the RF MEMS switch is fabricated and characterized successfully. The measured isolation, pull-in voltage, and insertion loss, are − 30 dB, 23 V, and − 0.2 dB, respectively at 18 GHz frequency. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.